i.mx 6ULL Burn eFUSE(SDMMC MFG mode)

[kevin_chuang]

我們的設計為SD1為SD card、SD2為eMMC。

我們出貨時，會插入SD Card(內部有code，當作恢復原廠設定使用)連同出貨，但我們客戶需要自行去更新eMMC，因此需要在有eMMC和SD卡同時存在的狀態下去進入Serial download mode。

因此從6ULL的設計上來看，是需要將SDMMC MFG mode做disable的。

請問如果將SDMMC MFG mode disable的功能是?如果disable有什麼風險?

如何燒斷0x470 bit3的SDMMC MFG mode的功能?

[kevin_chuang]

Hi Kunal Kotecha,

Thanks for your idea! 

But we can't reserve the hole to plug or pull SD card in our product....the customer request....

Thanks!

Kevin Chuang

[kunalkotecha1]

Hi kevin.chuang@youngoptics.com,

Then I believe as per the flow you should disable SDMMC manufacture mode. I kept a thought and feel that your other requirements will be fulfilled even after disabling SDMMC mode. However, I would suggest you verify all the requirements at your end as well.

Regards,

Kunal

[kunalkotecha1]

Hi kevin.chuang@youngoptics.com,

As per the below screenshot from RM, the device will go in SD/MMC manufacture mode if internal boot and recovery boot is failed or if boot mode pins are set to serial download mode. But I believe in your case your system is not failing to boot.

What is the value of BOOT_MODE in your case? Do you want to remove the SD Card and flash eMMC? Also, if you want to disable the SDMMC MFG mode please refer Burning eFuses on i.MX6 and i.MX7 - i.MXDev Blog to burn the fuse.

Regards,

Kunal

[kevin_chuang]

Hi Kunal Kotecha,

We set BOOT_MODE is serial downloader(Boot0=1, Boot1=0).

We want to SD card and eMMC simultaneously exist in our product (function of SD card is recovery original setting)and then we want to enter serial download mode.

Do you have the other way except burn the fuse?

Thanks!

Kevin Chuang

[kunalkotecha1]

Hi kevin.chuang@youngoptics.com,

Let me frame as per my understanding and correct me if there is any misunderstanding.

You have a product that initially has an SD Card with flashed images. You are setting the BOOT_MODE to serial downloader mode. With serial download mode and SD Card flashed images you are shipping the product. Now, If you turn on the system, it will boot from SD Card as SDMMC mode is enabled by default.

If you disable SDMMC mode then, the system will directly go to Serial download mode and wait for image. Then you can download the image to eMMC.

However, my concern is lets say once you downloaded the image to eMMC, then you need to set the BOOT_MODE pin to internal boot and eMMC as the boot device. If so, then you will always boot from eMMC and I don't know when the SD Card will be used further. Please clear me if with exact scenario if there is any difference.

Regards,

Kunal

[kevin_chuang]

Hi Kunal Kotecha,

Our product have MCU to control the pin level of CPU Boot mode & Boot configure and we will control different mode(serial download or internal boot)  via button.

We always use eMMC to boot 6ULL.

If we want to recovery eMMC to original setting, we will use SD card to boot and download firmware to eMMC.

SD1→SD card, SD2→eMMC

So we will let eMMC and SD card with code simultaneously exist in our product.

Our customer need to update eMMC firmware through USB so we need to enter serial download. 

But we can't enter serial download mode if eMMC and SD card with code simultaneously exist.

Do you have the other way except burn the fuse?

Thanks!

Kevin Chuang

[kunalkotecha1]

Hi kevin.chuang@youngoptics.com ,

Okay. As the customer is using serial download then the board will be physically available with him and in this case, I believe if they remove the SD Card from the socket then as per the flow it will scan SD1, and if not found it will jump to Serial Download mode. From next time you can continue with the flow as per your requirement.

Regards,

Kunal